Paratelecrinus cubensis

Messing, Charles G., 2013, A revision of the genus Atelecrinus PH Carpenter (Echinodermata: Crinoidea), Zootaxa 3681 (1), pp. 1-43 : 22-25

Paratelecrinus cubensis PH Carpenter, 1881

Figures 9 , 10

Antedon cubensis Pourtalès 1869:356 (part); 1878:214–215 (part).

Atelecrinus cubensis PH Carpenter 1881:15 –19, pl. 1, fig. 7; 1882:491–492; 1888:70–72.—AH Clark 1907:155.— Hartlaub 1912:281, 386, 484, pl. 14, figs. 3, 8, 9.

Atelecrinus pourtalesi AH Clark 1907:4.— H.L. Clark 1941:13.

Atelecrinus balanoides : AH Clark and A.M Clark 1967:819, 823–831 (part).

Neotype. USNM E42652 , JSL I 2005, French Bay, San Salvador I, Bahamas, 23º55’03”N, 74º31’40”W, 800 m, 23 Apr 1987, D. Pawson and P. Kier, colls.

Other material examined. Bahama Islands: USNM E42670 , JSL I 1501, New Providence I., 24º59’59”N, 77º34’34”W, 705 m, 20 Oct 1987, J. Miller and C. Norlund, colls. (2 spec.); USNM E42671 , JSL I 1501, New Providence I, 24º59’59”N, 77º34’34”W, 757 m, 20 Oct 1987, J. Miller and C. Norlund, colls. (1); USNM E42683 , JSL II 813, Eleuthera I., 25º30’51”N, 76º55’01”W, 751 m, 12 Apr 1984, D. Pawson and G. Hendler, colls. (1); USNM E42684 , JSL II 813, Eleuthera I., 25º30’51”N, 76º55’01”W, 768 m, 12 Apr 1984, D. Pawson and G. Hendler, colls. (1); USNM E42693 , JSL I 2268, Crooked I., 22º41’24”N, 74º21’18”W, 890 m, 15 Sep 1988, D. Pawson and D. Billett, colls. (1); USNM E42694 , JSL I 2264, San Salvador I., 24º03’37”N, 74º33’22”W, 876 m, 13 Sep 1988, D. Billett and G. Hendler, colls. (1); USNM E42695 , JSL I 2261, Exuma Sound, 23º50’45”N, 75º09’36”W, 832 m, 12 Sep 1988, P. Kier and Peterson, colls. (1); USNM E42696 , JSL I 2274, Acklins I., 22º36’30”N, 73º38’36”W, 835–843 m, 18 Sep 1988, G. Hendler and E. Balser, colls. (2); USNM E43082 , JSL I 2267, Crooked I., 22º42’N, 74º22’W, 892 m, 15 Sep 1988, J. Miller and Peterson, colls. (1); USNM 43083, JSL II 1497, Andros I., 25º12’12”N, 77º59’56”W, 789 m, 18 Oct 1987, G. Hendler and C. Norlund, colls. (1). Cuba: MCZ 1073, Atlantis 3341, Golfo Cazones, 21º59’N, 81º20’W, 567–778 m (1).

Diagnosis. A species of Paratelecrinus with 10 columns of cirrus sockets and Iax2 hexagonal or rhombic with thin, often wing-like lateral flanges. Interradial margin of centrodorsal concave or with a deep V-shaped excavation ( Figures 9 a–c).

Description of the neotype. Centrodorsal conical, broadest across level of peripheral sockets; basal diameter 3.0 mm, HD 1.3; interradial margin with often deep triangular or U-shaped excavation; midradial margin with small triangular projection; very weak interradial ridge adjacent to centrodorsal base; apex with thin weak glassy ridges; fulcral tubercles strongly projecting and triangular. Cirri ~XLV (too crowded to count accurately); detached intact peripheral cirrus (broken during examination) 94 mm long, of 45 segments; c1–2 short; following increasing in length, becoming compressed with expanded distal ends; c8–18 longest, LW 6.7; distal few cirrals tapering; distal three cirrals preceding claw with a weak aboral spine; antepenultimate and penultimate cirrals squarish. Apical cirrus of 28 segments, 19 mm long.

Basals forming a complete ring well separated from centrodorsal, especially interradially, by a distinct ligament bundle; externally visible portion of basals swollen interradially, narrowing laterally and expanding to elongated oval ends accommodated by shallow concavities in centrodorsal margin on either side of small midradial projection. Radials short, WL 3.3; profile 100°; lateral margins visible between bases of rays, separating adjacent brachitaxes. Longest attached ray 120 mm long, complete to just beyond last pinnule; arm tip a slender filament lacking pinnules composed of slender brachials with expanded ends (similar to distal pinnulars or middle cirrals); longest intact filament 32 mm long, of 40 brachials following distalmost pinnule (now detached). Brachitaxes and proximal brachial pair with moderately developed synarthrial swellings. Ibr1 separated laterally, roughly oblong with V-shaped distal margin; WL 2.3; lateral margins with a thin flange sheathed in transparent tissue and depressed toward center of body, sometimes with a small triangular spine just in front of flange. Iax2 rhombic; WL 1.2; with transparent wing- or ear-like flanges; distal portion parallel-sided; proximal margin V-shaped. IIbr1 longer exteriorly, slightly separated over axil; WL 3.1; exterior lateral margin with thick ridge or flange. IIbr2 irregularly quadrate, longer exteriorly and wider distally; proximal margin V-shaped; WL 1.3; exterior lateral margin not thickened; well-developed gap between adjacent IIbr2 on each ray. IIbr3+4 longer interiorly; WL 1.1; 1.7 mm across. Middle brachials wedge-shaped; WL 1.1; alternating articular tubercles present on IIbr7–8 and following brachials. Syzygies at 3+4, 6+7, 10+11 and chiefly at intervals of 2 (sometimes 3) muscular articulations.

Description of other specimens. Centrodorsal conical, often with convex sides, sometimes with weak (rarely strong) interradial ridge near base; basal diameter 1.5–3.0 mm; HD 1.1–1.4; interradial margin concave or with a deep V-shaped excavation accommodating ligament bundle; midradial margin with a pair of shallow concavities accommodating ends of adjacent basals. Apex rounded or truncated, often with thin weak ridges extending to tip from apical cirrus socket tubercles. Cirrus sockets in 2 columns per radial area, chiefly 4–5 per column (rarely 3 or 6), with strongly projecting, triangular fulcral tubercles. USNM E42681 from Barbados bears a third middle column of 1–2 sockets in 4 radial areas (similar to P. orthotriremis below).

FIGURE 10. Paratelecrinus cubensis ( PH Carpenter) Iax2 illustrating changes in shape with increasing size from hexagonal with almost parallel sides to more rhombic. a. USNM E42683 . b. USNM E42652 . c. USNM E42696 . d. USNM E42695 . Dashed lines indicate bases of thin lateral flanges. Scale bar: 1 mm.

Cirri chiefly broken, ~XX– LVII (often too crowded to count accurately), longest intact of 45 segments, 94 mm long; c1 short; c2 short or squarish; following cirrals increasing in length, becoming compressed with expanded distal ends; up to ~11 middle cirrals equally long, with LW ~6–8; cirrals becoming shorter distally but still compressed; cirrus tapering near tip; up to 3 terminal cirrals (except claw) with weak distal aboral spine; penultimate cirral with LW 1.0–1.3; claw slightly shorter to longer than preceding segment, with distal half usually abruptly narrower and curved ( Figure 9 d). Apical cirri delicate, with as few as 23 segments, 8 mm long; distal several cirrals shorter than in larger cirri, with LW 2.0 and decreasing to tip; up to 4 terminal cirrals (except claw) with weak spine.

Externally visible portion of basals shallow chevron-shaped, interradially swollen, narrowing laterally and then expanding to rounded lateral ends, and forming a low complete ring. Large ligament bundle visible between middle of basal and concave interradial margin of centrodorsal. Lateral portions of basals either slightly separated from or abutting centrodorsal. Radials short, with concave distal margin and diverging lateral margins; WL 3.8–5.2 (as little as 2.1 in smaller specimens); radial profile 80° in small specimen, up to 120° in large specimens.

Ibr1 separated laterally, roughly oblong with V-shaped distal margin; WL 2.4–3.1; lateral margins with thin flange widest distally (ossicle sometimes appearing to have converging lateral margins with flange depressed toward center of body), sometimes with small triangular spine just in front of flange (both lateral features absent in smaller specimens); smaller specimens with WL 1.4–1.7. Iax2 hexagonal in small specimens ( Figures 9 a, 10a–b), becoming more rhombic with increasing size ( Figures 9 b–c, 10c–d); WL 0.9–1.0, longer than wide in smaller specimens; lateral margins with thin often transparent and wing-like flanges best developed in small specimens ( Figures 9 a, 10a); synarthrial swelling usually present.

Ray length to ~ 152 mm. Slender apinnulate distal arm filament of up to ~100 slender brachials. IIbr1 longer exteriorly, just in contact interiorly over axil; WL 2.4–3.1 (2.0– 2.1 in smaller specimens); exterior lateral margin with short, thick adambulacral ridge or flange. IIbr2 irregularly quadrate, longer exteriorly and wider distally; WL 1.3–1.4 (0.9–1.0 in most smaller specimens); exterior lateral margin thickened or not; well-developed interior gap between adjacent IIbr2 on each ray. IIbr3+4 longer interiorly; 1.1–1.8 mm across; WL 1.1–1.3 (0.9 in smaller specimens). IIbr5 and following few brachials weakly to strongly wedge-shaped; WL 1.3–2.1 (chiefly 1.6–1.9, and 0.7 in smaller specimen). Middle brachials wedge-shaped to almost triangular, with one side much longer than the other; WL 0.9–1.7; alternating articular tubercles present on IIbr7–8 and following brachials. Distal brachials wedgeshaped and longer than wide, with distal and proximal ends smooth or raised aborally as weak alternating articular tubercles; WL 0.6–0.8. Syzygies at 3+4, 6+7 and 9+10; subsequently at intervals of 2 (occasionally 3) articulations. One specimen with 8+9; another lacking 3+4.

P1 on IIbr17, of up to 35 segments, 20 mm long; first pinnular short; second trapezoidal; following pinnulars becoming more slender and much longer with expanded distal ends; LW up to 10.0 (14.0 in small specimen); decreasing in length near tip. Several proximal segments beginning with third or fourth bearing a distal aboral spine.

Anal papilla central; mouth marginal or submarginal; ambulacra running from arms to mouth via narrow tissue bridges. Ambulacra on proximal portion of arms (to beyond P1) with sparse podia, apparently only 1–2 triads on each side of each brachial; triads accompanied by a pair of modified lappets with one saccule distal to lappet; lappet pairs sometimes resembling sessile pedicellaria (“pseudopedicellaria” of Messing 2003).

Distribution. Bahama Islands and north coast of Cuba in 705– 892 m. A single specimen from the south coast of Cuba was taken in 567– 778 m.

Remarks. Both PH Carpenter (1888) and AH Clark and AM Clark (1967) reviewed the history of Atelecrinus cubensis in detail, but a few comments should be added. In his preliminary work on the crinoids collected by the U.S. Coast and Geodetic Steamer Blake, PH Carpenter (1881) first recognized Atelecrinus cubensis as a distinct taxon and is the proper author, although he attributed the name to Pourtalès (1869, 1878), who included the original specimen ( U.S. Coast Survey steamer Bibb sta. 139P, off Havana) under the very different Antedon cubensis ( Pourtalès, 1869) (now Trichometra cubensis ). The Blake material turned over to Hartlaub following PH Carpenter’s death in October 1891 was in poor condition but included ten lithographic plates, one of which included re-engraved figures of At. cubensis and At. balanoides almost identical to those published by PH Carpenter (1881) ( Hartlaub 1912). Though AH Clark had substantially revised comatulid taxonomy between 1907 and 1909, Hartlaub felt bound to use PH Carpenter’s older system (AH Clark 1950:346). Hartlaub (1912) discussed At. cubensis under At. balanoides in his report on the Blake collection, and quoted a letter from AH Clark saying that At. cubensis was an immature At. balanoides . However, Hartlaub’s plate captions (nos. 6 and 14) distinguish the two. AM Clark (in AH Clark and AM Clark 1967: 830) wrote that the distinction suggested that Hartlaub “remained unconvinced” that the two were the same. However, Hartlaub may have simply continued PH Carpenter’s usage, having received plate number 6 with the two species distinguished.

In removing At. cubensis from synonymy under At. balanoides , I am designating a neotype because the original Bibb specimen was lost along with many Blake specimens some time after Hartlaub examined them. Although the lithograph of the Bibb specimen ( Carpenter 1881, pl. 1, fig. 7) and its derivative ( Hartlaub 1912, pl. 6, fig. 7) are quite schematic and do not reveal important species-level diagnostic features, a small photograph ( Hartlaub 1912, plate 14, figure 3) appears to show the thin lateral flanges on the axil unique to this species. No other specimens have been collected since from the north coast of Cuba. The neotype (USNM E42652 ), from the Bahamas, is the most complete specimen and exhibits several of the features distinguishing it from At. balanoides noted by PH Carpenter (1881) (though these are not the only diagnostic characters), e.g., more crowded cirrus sockets with more prominent fulcral tubercles; basals produced interradially, and stronger proximal projection of axils and IIbr2. The wider centrodorsal diameter-to-height ratio cited by PH Carpenter as distinguishing At. cubensis from At. balanoides overlaps widely in the two species.

Of the two other species of Paratelecrinus with cirri in ten columns, P. wyvilli from the western Pacific differs (from P. cubensis ) in having basals forming a thin band of almost uniform height rather than narrowing laterally and expanding again at their ends; Ibr1 with distolateral corners cut away, and rhombic axils lacking wing-like lateral flanges. P. amenouzume , from much deeper water off Japan, has well-developed narrow interradial ridges on the centrodorsal, proportionately more elongated IBr2, and a very shallow V-shaped articulation between Ibr1 and Iax2 with weak narrow synarthrial swelling.

Figures

FIGURE 9. Paratelecrinus cubensis (PH Carpenter). a – c. Centrodorsal and ray bases in lateral view. a. USNM E 42683. b. USNM E 42695. c. USNM E 42693. d. Two middle cirrals (upper) and tips of two cirri (middle, lower), USNM E 42693. Scale bars: lower (a – c), upper (d) both 1 mm.